Interleukin-1 receptors were identified in the mouse testis as well as in the mouse brain. In the brain, the receptors were characterized by binding techniques and localized by autoradiographic techniques. Similar studies were carried out in the mouse kidney. Also, an interesting interaction between CRF receptors and Interleukin receptors were found in ATT-20 tumor cells where treatment with CRF resulted in an upregulation of IL-1 receptors.